The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
The invention relates to a mooring assembly for a vessel, comprising a moonpool defined in the vessel, a turret rotatably mounted within the moonpool by means of an upper main bearing for transmitting horizontal and vertical loads between the vessel and turret and by means of a lower secondary bearing for substantially transmitting horizontal loads between the vessel and the turret, and mooring lines attached to the lower region of the turret.
Ideally the lower secondary bearing transmits the major part of the mooring forces (which are caused by the mooring lines) in a horizontal direction to the vessel. Practically, however, it is difficult to avoid that a substantial part of these forces are reacted by the upper main bearing, causing severe stresses, particularly in the turret and in the upper main bearing.
One suggested solution for this problem is to decrease the diameter of at least a lower part of the turret such as to reduce its resistance against bending. As a result the turret may bend under horizontal mooring forces, causing the lower secondary bearing to transmit most of the horizontal loads. A disadvantage, however, is that such a reduction of diameter of the turret reduces the available space for risers (or other elements such as, for example, a disconnectable buoy member) Further such a reduction of diameter may decrease the ability of the turret to transmit circumferential loads.